Biomedical subjects

A Piattelli

Publications and source records attributed to A Piattelli.

At least 91 records · Page 5Linked to original sources

PubMed1998

Immunohistochemical analysis of a dentinogenic ghost cell tumour.

A dentinogenic ghost cell tumour in an 80-year-old male patient is presented. It is an extremely rare tumour and only 10 cases have been reported in the English literature. The lesion showed odontogenic epithelium, ghost cells, dentinoid, giant cells. The immunohistochemical analysis for Mib-1 and bel-2 showed a strong positivity of the cells of the odontogenic epithelium, while with p53 only a rare positivity was observed. Completely negative were the ghost cells, giant cells and dentinoid material. In this tumour the cells expressing Mib-1 and bcl-2 could be the cells that proliferate, and that could undergo malignant transformation.

Aged↗

PubMed1998

Oral ulceration as a presenting sign of unknown sarcoidosis mimicking a tumour: report of 2 cases.

Oral lesions seem to be rather infrequent in sarcoidosis, and only 43 cases have been described in the English literature. Clinically most oral lesions appear as non-tender well-circumscribed swellings or submucosal nodules. Superficial ulceration is unusual. The authors present two cases in which the first presenting symptom of an unknown sarcoidosis was the presence of an oral ulcerated lesion with indurated margins that could easily have been misdiagnosed for a squamous cell carcinoma. It must be stressed that in all ulcerated lesions of the oral cavity, squamous cell carcinoma must always be considered in the differential diagnosis.

Adult↗

PubMed1998

Solitary fibrous tumour of the tongue.

Solitary fibrous tumour (SFT) is a neoplasm most often localised in the pleura and peritoneum. The tumour is composed of spindled fibroblastic cells arranged in a haphazard way. Recently SFT has been described in many locations. Only one case of oral SFT has been described in the cheek: this is the second case of an oral SFT located in the tongue. The differential diagnosis must be made from many soft tissue tumours. SFTs stain strongly, in almost all cases, for CD34.

Aged↗

PubMed1998

Histologic observations on 230 retrieved dental implants: 8 years' experience (1989-1996).

The histologic examination of dental implants retrieved from humans is important to establish the causal determinants of implant failure, and to compare and validate the results obtained from animal studies. This study presents a retrospective review of the histologic features of 230 implants retrieved in an 8-year period (1989-1996). All the implants were treated to obtain thin (20 to 30 microm) ground sections. The majority of implants were retrieved because of mobility (n=56), peri-implantitis (n=54), or fractures (n=90). Peri-implantitis occurred more frequently before (n=44) than after (n=10) abutment connection. A dense fibrous connective tissue with no inflammatory cells was present at the interface in the implants retrieved for mobility; bone was found only in the most apical part. In many of these implants epithelial cells were present. The main histologic features of peri-implantitis consisted of the presence of a bone sequestrum near the implant, many bacteria present on the implant surface, and an inflammatory infiltrate (macrophages, lymphocytes, and plasma-cells) nearby. Histology showed that in the implants removed for fracture, there was a very high percentage (80 to 100%) of peri-implant bone.

Animals↗

PubMed1998

Hollow implants retrieved for fracture: a light and scanning electron microscope analysis of 4 cases.

One of the possible complications of implant treatment is the occurrence of an implant fracture. Metal fatigue and biomechanical overload seem to be the most common causes of fractured implants. This study evaluated 4 implants (3 hollow cylinders and 1 hollow screw) which fractured after a mean loading period of 2.8 years. All implants had a 4 mm diameter and had been inserted in a posterior location. In 3 cases parafunctional habits were present. In all cases a vertical resorption of the peri-implant bone was present. The endosseous portion of the implant presented always a very high bone-implant contact percentage. Scanning electron microscopic examination showed that at least one of the implant holes was involved in the fracture line; no porosities or material defects were observed on the fractured surface of the implant. In hollow implants the holes could represent a site of less resistance.

Alveolar Bone Loss↗

PubMed1998

Immediate loading of titanium plasma-sprayed implants: an histologic analysis in monkeys.

Aim of this study was to evaluate peri-implant tissue reactions to immediately loaded titanium plasma-sprayed implants in Macaca fascicularis monkeys. A total of 48 titanium plasma-sprayed implants were inserted (24 in the posterior maxilla and 24 in the posterior mandible). A metal superstructure was cemented 3 days after implant insertion on 24 implants (12 in the maxilla and 12 in the mandible) (test implants). The remaining 24 implants (12 in the maxilla and 12 in the mandible) were left unloaded (control implants). Nine months after implant placement a block section was carried out, the defect filled with non-resorbable hydroxyapatite, and all 48 implants retrieved. The implants were treated to obtain thin ground sections. Three slides were cut for each implant and examined under normal and polarized light and a morphometrical analysis done. All implants were covered by bone under light microscopy. The histomorphometrical analysis demonstrated that in test implants, the bone-implant contact percentage was 67.3% (+/-7.6%) in the maxilla, and 73.2% (+/-5.9%) in the mandible; in control implants the percentages were, respectively, 54.5% (+/-3.3%) and 55.8% (+/-6.5%). In the test implants the bone around the implants tended to have a more compact appearance. In conclusion, our study demonstrated that in test implants the bone-implant contact percentage was significantly greater than in the controls (P < 0.01) and no fibrous connective tissue was present at the interface.

Alveolar Process↗

PubMed1998

Molar root furcation: morphometric and morphologic analysis.

The objective of the present study was a morphometric and morphologic analysis of maxillary and mandibular first and second molars using three different techniques. Measurements of 207 maxillary molars (105 first and 102 second molars) and 207 mandibular molars (110 first and 97 second molars) were measured; root length, radicular trunk length (RTL), mesiodistal and buccolingual diameters (BLD) at the cementoenamel junction, inter-radicular angle (IRA) width, and furcal roof area (FRA) were recorded. No significant statistical correlations were found for most of these measurements, the only exception being the relationship between IRA/FRA, IRA/BLD in maxillary molars, and IRA/RTL in the maxillary first molar. Morphologic examination was carried out by stereo microscopy, light microscopy of undecalcified sections, and scanning electron microscopy. All of these techniques showed the complexity of the furcation area with a large number of anatomic irregularities and plaque-retentive structures that could hamper adequate cleaning during periodontal treatment.

Humans↗

PubMed1998

Microscopic and histochemical evaluation of demineralized freeze-dried bone allograft in association with implant placement: a case report.

A case report is presented in which a titanium implant was placed into a defect resulting from the extraction of an impacted tooth; the defect was filled with demineralized freeze-dried bone allograft particles without a membrane barrier. After a 6-month healing period the bone defect had completely healed and the tissue present had macroscopic features similar to mature bone. Histologic examination of this tissue showed that, in all demineralized freeze-dried bone allograft particles, mineralization nodules were scattered inside the demineralized bone; in the areas where the mineralization nodules were present, osteocyte lacunae could be observed. In the case presented, significant new vital bone formation was observed 6 months after placement of a demineralized freeze-dried bone allograft.

Acid Phosphatase↗

PubMed1998

Vertical ridge augmentation around dental implants using a membrane technique and autogenous bone or allografts in humans.

This study investigated the effect on vertical bone regeneration of the addition of demineralized freeze-dried bone allograft or autogenous bone chips to a membrane technique. Twenty partially edentulous patients with vertical jawbone deficiencies were selected for this study. The patients were divided into two groups of 10 individuals. The 10 patients of Group A received 26 Brånemark implants in 10 surgical sites. The 10 patients of Group B received 32 implants in 12 surgical sites. Fifty-two out of 58 implants (22 in Group A and 30 in Group B) extended 1.5 to 7.5 mm superior to the bone crest. Titanium-reinforced expanded polytetrafluoroethylene membranes were used to cover the implants and, before complete membrane fixation, demineralized freeze-dried bone allograft particles were condensed under the membrane in Group A, and autogenous bone chips were used in Group B. At the reentry after 7 to 11 months the membranes were removed and a small biopsy was collected from 11 sites comprehending the miniscrews. The clinical measurements from Group A demonstrated a mean vertical bone gain of 3.1 mm (SD = 0.9 mm, range 1 to 5 mm) with a mean percentage of bone gain of 124% (SD = 46.6%). The measurements from Group B showed a mean vertical bone gain of 5.02 mm (SD = 2.3 mm, range 1 to 8.5 mm) with a mean percentage of bone gain of 95% (SD = 26.8%). Histomorphometric analysis of the present study clearly demonstrated a direct correlation between the density of the pre-existing bone and the density of the regenerated bone. The mean percentage of new bone-titanium contact was from 39.1% to 63.2%, depending on the quality of the pre-existing bone. Both the clinical and histologic results indicate a beneficial effect of the addition of demineralized freeze-dried bone allograft or autogenous bone particles to vertical ridge augmentation procedures in humans.

Adult↗

PubMed1998

Implant periapical lesions: clinical, histologic, and histochemical aspects. A case report.

A new entity, the "implant periapical lesion," has recently been described. The etiology of this condition could be attributed to overheating of the bone, overloading of the implant, presence of a pre-existing infection or of residual root particles and foreign bodies in the bone, implant contamination during production or during insertion, or placement of the implant in an infected maxillary sinus. In this report, a titanium plasma-sprayed implant had been inserted into the mandible of a 53-year-old patient; after 5 months a fistula developed and periapical radiography showed a large radiolucent image around the apical portion of the implant. The implant was removed, and histologic examination showed necrotic bone and an inflammatory infiltrate inside the hollow portion of the implant. The etiology of the implant failure in this instance could be related to a fracture and vascular impairment of the bone inside the implant during insertion, to external contamination of the implant, or to the poor bone quality of the implant site.

Alveolar Process↗

PubMed1997

Human herpesvirus 8 variants in sarcoid tissues.

BACKGROUND: The cause of sarcoidosis is unknown, although mycobacteria have been implicated. We examined sarcoid tissues for human herpesvirus 8 (HHV-8) in addition to mycobacterial genomic sequences. METHODS: Biopsy samples from 17 patients with sarcoidosis were studied (eight transbronchial, 27 lymph node, two skin, and two oral mucosa). We used tissues (n = 137) from 96 patients without sarcoidosis as negative controls. A nested PCR was applied to amplify a segment of open reading frame (ORF) 26 of the HHV-8 genome, and a heminested PCR was to amplify a segment of ORF 25 of HHV-8 and of the 16 S rRNA gene of mycobacteria. Differences in base sequences of the amplified fragments were resolved with single-strand conformation polymorphism and dideoxy sequencing. FINDINGS: HHV-8 ORF 26 DNA was detected in significantly higher proportions of sarcoid than of non-sarcoid tissue samples from lung (8/8 vs 0/54; p < 0.0001), lymph nodes (26/27 vs 6/29; p < 0.0001), skin (2/2 vs 0/17; p = 0.006), and oral tissues (2/2 vs 1/13; p = 0.029). 31 (82%) of the 38 ORF 26 DNA-positive sarcoid specimens were also positive for ORF 25 DNA. For mycobacteria-like 16 S rRNA DNA, the proportion positive was significantly higher in sarcoid than non-sarcoid tissues for lymph node samples (11/27 vs 2/29; p = 0.003) but not for other tissues (lung 3/8 vs 22/54; skin 2/2 vs 15/17; and oral tissues 1/2 vs 0/13). Overall, the prevalence of HHV-8 ORF 26 sequences was higher in sarcoid tissues than in non-sarcoid tissues (p < 0.0001). When patients whose tissues were included in a masked phase of the study were treated as units of analysis, eight of eight sarcoidosis patients were positive for HHV-8 ORF 26 DNA, compared with three of 56 control patients (p < 0.0001); for mycobacteria-like sequences, three of eight sarcoidosis patients were positive, compared with four of 56 controls (p = 0.0464). The HHV-8 ORF 26 sequences, ten of which were unique, could be segregated into four groups according to peptide motifs. In seven of nine patients from whom biopsy samples were taken from various sites, different sequences were recovered. The mycobacterial sequences amplified from sarcoid tissues were also varied, but none was homologous to those of known species. INTERPRETATION: Variant HHV-8 DNA sequences are found in a wide range of sarcoid but not non-sarcoid tissues. Mycobacteria-like 16 S rRNA sequences are more frequently present in sarcoid lymph nodes and not in other tissue types, but do not indicate infection by a particular mycobacterial species.

Adult↗

PubMed1997

Clinical and histological results in alveolar ridge enlargement using coralline calcium carbonate.

A very important parameter during the insertion of dental implants is the amount of bone present in a site. A regenerative procedure to increase the width and the height of bone is proposed with the use of occlusive barrier membranes and biomaterials. The authors used, in six patients with deficient alveolar ridges, prior to implant insertion, Biocoral gel particles in connection with expanded polytetrafluoroethylene membranes. After 6 months it was observed that a tissue similar to mature bone had regenerated under the membrane and microscopically it was observed that the Biocoral particles were still present and almost all were completely surrounded by mature bone.

Adult↗

PubMed1997

Resorption of composite polymer-hydroxyapatite membranes: a time-course study in rabbit.

The histological findings in rabbit, concerning the resorption of a new composite hydroxyapatite-polymer membrane used in guided tissue regeneration are reported. The polymer appeared to be completely resorbed in about 4-6 months, while the inorganic component, hydroxyapatite, appeared to begin to resorb after the tenth month. The integrity of the membrane appeared to be unchanged after a 10-month period. No inflammatory cell infiltrate was present. This new type of membrane appeared to be relatively well tolerated by the host, had no significant adverse soft and hard tissue reaction, appeared to be easy to handle and had good space-maintaining capabilities. More research is certainly needed before clinical use in man.

Absorption↗

PubMed1997

Simultaneous demonstration of alkaline and acid phosphatase activity in bone, at bone-implant interfaces and at the epiphyseal growth plate in plastic-embedded undemineralized tissues.

The aim of the present study was to determine if it was possible to detect in bone, at the epiphyseal growth plate and at the bone-implant interface, the presence of alkaline and acid phosphatases using Technovit 7200 VLC resin. In the plastic-embedded specimens it was possible to observe the simultaneous presence of acid and alkaline phosphatases at the epiphyseal growth plate in the presence of intra-articular implants. The morphology of the cells positive for the phosphatases was very clear, with no apparent diffusion of the reaction product and no sputter ground staining.

Acid Phosphatase↗

PubMed1997

High-precision, cost-effective cutting system for producing thin sections of oral tissues containing dental implants.

A new high-precision, cost-effective cutting system, able to produce thin (20-30 microns) sections of oral tissues, containing dental implants, is presented. With this system the authors have been able to obtain, in a reproducible and consistent way, thin slides containing biomaterials and biological tissues. Very high cellular detail was possible, even at high magnifications (x 1200). Histochemical reactions (e.g. acid and alkaline phosphatases) have also been obtained in a reproducible way, without sputter ground staining. The time involved in specimen cutting was significantly reduced, and about five slides per specimen were obtained with minimal loss of tissue. In almost all cases it has been possible to eliminate the grinding process with its inherent problems, such as formation of ledging at the bone-titanium interface. With this system it was also possible to obtain thin slides of soft tissue lesions (i.e. benign mucous membrane pemphigoid).

Acid Phosphatase↗

PubMed1997

Histological and histochemical analyses of acid and alkaline phosphatases around hydroxyapatite-coated implants: a time course study in rabbit.

One of the concerns pertaining to hydroxyapatite (HA)-coated dental implants is their possible dissolution over time, with ultimate loss of the implant. HA-coated dental implants were inserted medially into rabbit femoral articular knee joints. The implants were retrieved after 1 week, 1 month, 3 months and 6 months. At 1 week, many alkaline phosphatase (ALP)-positive osteoblasts were observed near the implant surface. No signs of degradation of the coating were present. At 1 month, only few ALP-positive osteoblasts were present in the marrow spaces at the interface with the coating. Many acid phosphatase (ACP)-positive cells were observed near the coating. In many marrow spaces the HA coating was reduced in thickness. At 3 months, a further reduction of the thickness of the coating, in the areas in contact with marrow spaces, was seen. Many ACP-positive cells were present in tight contact with the coating. Few ALP-positive osteoblasts were present. At 6 months, in many areas in contact with marrow spaces, the HA coating was completely resorbed. The histological and histochemical results seem to point to the existence of two types of ACP-positive cells: multinuclear, often in the process of phagocytosing HA particles, and mononuclear, with a morphology similar to osteoclasts.

Acid Phosphatase↗

PubMed1997

Squamous odontogenic tumour: report of two cases.

Squamous odontogenic tumour is a benign odontogenic tumour composed of a well-differentiated squamous epithelium immersed in a fibrous connective tissue stroma. It is a rare tumour and a recent literature review yielded only 36 cases. Two cases of squamous odontogenic tumour are presented, 1 located in the maxilla and the other in the mandible: 1 of these cases showed a periodontal involvement. The radiographic picture was fairly characteristic in 1 case, with a radiolucent lesion between the roots of the second mandibular premolar and the first molar, while, in the other case, it was possible to observe the presence of a lesion located at the apex of a molar. The tumours were enucleated, and no recurrences were observed after 5 years.

Adult↗

PubMed1997

Ameloblastic fibro-odontoma: report of two cases.

Ameloblastic fibro-odontoma is a rare odontogenic tumour. It affects young people and is usually located in the posterior jaws. Two cases of this tumour are presented: both lesions had produced an asymptomatic swelling. The histology showed the presence of an odontogenic epithelium immersed in a fibrous mesenchyme; dental hard tissues were also present. No recurrences were found after 12 and 4 years from the surgical enucleation of the tumour.

Child, Preschool↗